No abstract

Burkholderia pseudomallei is the causative agent of melioidosis, a disease with high morbidity that is endemic in South East Asia and northern Australia. An unusual feature of the bacterium is its ability to induce multinucleated giant cell formation (MNGC), which appears to be related to bacterial pathogenicity. The mechanism of MNGC formation is not fully understood, but host cell factors as well as known bacterial virulence determinants are likely to contribute. Since members of the tetraspanin family of membrane proteins are involved in various types of cell:cell fusion, their role in MNGC formation induced by Burkholderia thailandensis, a mildly pathogenic species closely related to B. pseudomallei, was investigated. The effect of antibodies to tetraspanins CD9, CD81, and CD63 in MNGC formation induced by B. thailandensis in infected mouse J774.2 and RAW macrophage cell lines was assessed along with that of recombinant proteins corresponding to the large extracellular domain (EC2) of the tetraspanins. B. thailandensis-induced fusion was also examined in macrophages derived from CD9 null and corresponding WT mice, and in J774.2 macrophages over-expressing CD9. Antibodies to CD9 and CD81 promoted MNGC formation induced by B. thailandensis, whereas EC2 proteins of CD9, CD81, and CD63 inhibited MNGC formation. Enhanced MNGC formation was observed in CD9 null macrophages, whereas a decrease in MNGC formation was associated with overexpression of CD9. Overall our findings show that tetraspanins are involved in MNGC formation induced by B. thailandensis and by implication, B. pseudomallei, with CD9 and CD81 acting as negative regulators of this process.

In the original article, incorrect Figures were published with incorrect captions. The correct Figs. 1, 2, 3, 4, 5, 6, 7 and 8 and captions are given below.

Pathogenic bacteria are still considered the most global problematic issue, and they have a significant impact on human health, particularly the Enterobacteriaceae bacteria. This study aimed to investigate the frequency of the pathogenic bacteria and the related risk factors among patients in Duhok, Iraq. A total of 700 samples (281 from males and 419 from females) from Duhok Teaching Hospital were recruited and analysed. All samples were routinely cultured and identified based on their cultural and biochemical characteristics. Furthermore, the diagnosis was confirmed by using the Vitek2 system. The results showed that the highest rate was for Staphylococcus aureus (31%), and the lowest rate was for Candida albicans (4.4%). The other infections varied in their rates and included 27.7% E. coli, 9.4% Klebsiella pneumonia, 6.1% Acinetobacter pneumonia, 6% Streptococcus spp., 5.4% Enterobacter spp., 5.1% Pseudomonas aeruginosa and 4.7% Proteus mirabilis. Furthermore, the bacteria were mostly recovered from urine (67.1%) and swab (19.6%) specimens. The infection rate was higher in females (58.3%) than males (41.7%). This study suggested that the incidence of pathogenic bacteria is high in Duhok, Iraq. However, it was comparable to the global bacterial pattern with the domination of S. aureus and E. coli.